Method and apparatus for manufacturing fluorescent lamps



p 21, 1948. H. D. BLAKE EI'AL IETHOD AND APPARATUS FOR IANUFACTURING FLUORESCENT LANPS Filed Sept. 6,1946

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IE'I'HOD AND APPARATUS FOR MANUFACTURING 1 FLUORESCENT LAMPS 2 Sheets-Sheet 2 med Sept. e. 1945 lnven't'ors: Harpld D. Blake, WiH'ord J. Wirmh1 g ho++ jMMJ L/wn heir- Alr=fovne3.

Patented Sept. 21,1948

METHOD AND APPARATUS FOR MANU- rac'ruamo rwoaascan'r LAMPS Harold D. Blakeand Wilford J. Winninghoflt Cleveland HeightsrOhio, aslignors to General Electric Company, a corporation of New York Application September c.1946, Serial No. 095.284

'1': Claims. (01. sic-1) Our invention relates to methods and apparatus for manufacturing electric fluorescent lamps and similar electric devices. More particularly, our invention relates to methods and apparatus for performing the heat-produced scalingin and baking operations and then the exhausting and filling operations in the manufacture of electric fluorescent lamps.

Operations in the manufacture of the common form of fluorescent lamp provide for the application of a coating containing a fluorescent material to the lamp bulb, the baking or heat treatment thereof to separate the binder from the coating, the further heating of the lamp parts in the sealing-in of electrode mounts to the ends of the bulb, and the exhaustion of the lamp. With this combination of operations are also included for convenience, the operations of heat treating the lamp to release the occluded elements therein, heating of the cathode of the lamp to cause activation thereof and filling-of said lamp with an ionizable gas and discharge supporting materials. All of the manufacturing operations have been i performed in relatively large automatic machines heretofore which machines permit the more favorable grouping, of the operations and which give the finenessand uniformity of control necessary for successful completion of said operations. The grouping of the operations has to a certain extent been formulated with regard to the convenience of making such high speed automatic machines and to other manufacturing problems and has burdened the manufacture with a procedure in some ways-detrimental to the lamp.

One object of our invention is to provide methods and apparatus for manufacturing fluorescent lamps which avoid contamination of the fluorescent coating and the interior parts of an electric fluorescent lamp during the course of manufacture. Our invention provides a particular sequence of lamp making operations which greatly reduces the possibility of contamination of the taminating elements until the quent cooling can cause air and contamination to" be drawn into it.

Anotherobject of our invention is to provide a I method and apparatus having a continuous .se-

quence of lamp manufacturing operations which allowsmanufacture of a fluorescent lamp of higher efliciency and of greater efficiency maintenance throughout the life thereof. The present advantages of our invention are realized,

apart from a reduction in the contamination in the lamp, in a reduction in oxidation etc. of the fluorescent coating and the elimination of any reabsorption in said coating of gases driven oif during the heat treatment. The lamps pass rapidly through the manufacturing operations which are arranged so as to reduce the period of time for contamination and other injurious effects to take place to an absolute minimum and permit the exhaustion anddevelopment of a controlled atmosphere about the lamp parts to reduce more effec tively said contamination and injurious effects. Our invention also prevents the condensation of the products separated by the heat treatment from the fluorescent coating and other lamp parts on the surface of all parts of the lamp and the complex interstices of manufacturing apparatus.

Another object of our invention is to provide a method and apparatus for the more economical manufacture of fluorescent lamps. Our present object realizes a saving in time in the manufacture of the lamp by reducing the number of separate steps taken therein and, in certain instances, by decreasing the time required for said steps.

' manufacturing apparatus is also realized as well lamp parts by the absorption, condensation and deposition of gases, water vapor and other foreign material thereon. The methods are particularly characterized by the requirement that the fluorescent coating, which is applied to the inner surface of the bulb prior to the sealing of the electrode assemblies thereto, be heat treated durmg the exhaustion of the lamp or immediately prior thereto. By heat treating the fluorescent coating at such times, the period of time during which the finally treated coating is exposed to contamination is materially reduced andsaid coating is more effectively closed oil from conas a considerable saving in labor, fuel and floor space. According to our invention a single heat treatment serves to condition the fluorescent coating and to condition the lamp parts in the manner usually associated with the exhausting operation in the manufacture of the lamp.

A still further object of our invention is to provide a method and apparatus affording more ready and accurate control of the time and temperature elements of the heat treating operation in the manufacture of a fluorescent lamp. The invention allows ready adjustment or re-establishment of another heating scheduleto accommodate changes in the fluorescent. coating, brought on by short runs of different colored coatings for instance, and to care for indicated lamp is finally sealed. The method of operation eliminates the heating of the bulb in a period when any subse- I variations in lamp parts and changes In lamp design disturbing the manufacturing schedule.

Other objects and advantages of our invention will appear in the following detailed description of the methods and apparatus disclosed in the drawings.

In the drawings, Figs. 1 to 6 inclusive are side elevations of the lamp, Parts and associated apparatus in various steps in the course of the treatment and manufacture of a fluorescent lamp; Fig. 7 is a schematic plan view of apparatus for the manufacture of fluorescent lamps in accord with our invention; and Fig. 8 is similar schematic plan view of another embodiment of apparatus for said manufacture.

The first step in the course of the fluorescent lamp manufacture presented in the dnawings is the coating of the interior of the tubular bulb I as shown in Fig. 1 by flushing a fluid comprising a cellulosic binder having the fluorescent powder I in suspension therein over the entire interior'surface of the bulb. The coating fluid is preferably discharged from' a nozzle 2 introduced in the upper end of the bulb I and is directed about the full inner diameter of the tubular bulb I by the enlarged end of the valving pin 3. A sufficient quantity of the coating fluid is introduced into I the bulb I to cause an even flow thereof over the length of the bulb I and the draining of a quantity into the trough 4. The bulb I is allowed to remain in the position shown until there is no longer any drainage and the coating dries to a point where it will not-be disturbed by handling of the bulb I. Both the coating and drying operations are preferably preformed in automatic high speed apparatus of the type disclosed in United States patent application Patent 'No. 2,415,512, filed November 16, 1943, by John J. Malloy and assigned to the present assignee. Prior to passing on to the succeeding manufacturing operation the coatingmust be removed from a very limited area about the rim of both ends of the bulb I either by wiping or brushing.

According to our invention the coated bulb I is now subject to an operation sealing theelectrode carrying mounts and 5' into the opposite ends thereof as shown in Figs. 2 and 3. The mounts 5 and 5' are of the usual design having a flared stem tube 6. adapted to closethe open ends of .the bulb I and are preferably sealed therein in apparatus which first seals the mount 5 in one end of the bulb I and'which then, afterthe bulb I is turned end for end, seals the second mount 5' in the opposite end of said bulb I. The stem tube 6 of each mount 5 or 5 supports the electrodes of the lamp which consist of a filamentary cathode I of coiled metal wire, coated with a. still incompletely treated activation material, and wire anodes (not' shown) and provides connections to the cathode I and anodes through the leading-in wires 8. A passage through the stem 'tube 6 of both mount 5 and 5', in this particular instance, is connected to a vitreous exhaust tube 9 or 9, as the case may be, so as to permit the exhaustion and insertion of materials into the bulb I after mounts 5 and 5 have sealed the ends of said bulb I. The preferred form of apparatus used in a subsequent operation permits the exhaust tube 9' at one end of the lamp to be very short; however, the length of said tube 8' is not relevant to the proper carrying out of my invention. As shown in Fig. 2 one endof the bulb I and the stem tube 8 of mount 5 are sealedtogether by the flames from burners III while, a column of air under pressure Is established in the bulb I to prevent the flow of exhaust fumes etc. from the flames from entering said bulb I by the jet of air directed Into said bulb I from the nozzle II located thereabove. A relative rotative movement is preferably developed between the lamp parts I and 8 and the burners In to cause an even treatment of the seal. The stem tube 6 of the mount 5' is sealed to the other end of the bulb I, after it is inverted, byiiames from the burners I2 (Fig. 3). In this instance an air pressure is again created in the bulb I to prevent the exhaust gases etc. from entering the bulb I by a Jet of air directed into the end of the exhaust tube 9 from the nozzle I3.

Apparatus for sealing the stem tubes 6 into withsuch modifications therein to produce air pressure in the bulb I during the sealing operation as disclosed in'United States patent application Serial No. 530,952, R. H. Stuart, filed April 14, 1944. Both of the above patent applications are assigned to the assignee of the present invention. v

The following steps in the instance disclosed in Figs. 4,5, and 6 in the manufacture of a fluorescent lamp are performed while in a somewhat separate portion of apparatus in which the now completely assembled lamp I4 is held in a head I5 and by which said lamp'l4 is advanced into operative relation with certain other apparatus by the regular indexing movements thereof. The head I5 provides a port corresponding to that in the usual exhausting apparatus for holding and making a gas-tight connection to the exhaust tube 9 which exhaust tube 9 is upon insertion of lamp I4 into the head I5 directed through the conical central opening in the washer I5 and the rubber washer IT to the extent permitted by the opening in the insert I8. After the exhaust tube stakes its proper relation in the head I5, the arm I9 is turned so as to screw the cap 20 further onto the body 2| of the head I 5 and compresses the rubber washer I1 thereby causing said exhaust tube 9 to be gripped and held, and a leak-proof connection is made to said lamp I4. Additional means are also provided in the pairs of Jaws 54 and 55 for gripping and holding the bulb I in proper relation in the head I5 to avoid strain on the exhaust tube 9 duringthe movements thereof which advance the lamp I4 into operative relation to apparatus at a. sequence of work stations for the further treatment thereof.

The head I5 takes a course of movement which first causes the lamp 14 to be introduced into an oven 22 (Fig. 4) maintained at sufllciently high temperature to burn out the binder of the coating on the inner surface of the bulb I and cause the dissipation and extraction of the occluded gases from the bulb I and other parts of the lamp I4. The temperature and length of .the heat treatment is so limited as to prevent any over treatment producing a reduction in the efllciency of the particular fluorescent material on the inner surface of the bulb I. phosphors can effectively be treated in'the temperature-range between 400 and 600 C. and for of the lampcauses the interior of the lamp to The current fluorescent becomecontaminated with the products of the burningiof the binder in the fluorescent coating and such gases etc. that are driven from the lamp parts which products, gases and other foreign materials are caused to be exhausted from the lamp I4 by the fiow of a gaseous medium into the exhaust tube 9 at one end of the lamp and out the exhaust tube 9' at the other end thereof. In this particular instance the discharge of the foreign materials is brought about by the very gradual flow of air from the exhaust head iii to the lamp through the exhaust tube 9 and a corresponding outward flow of the air mixed with the foreign material through the exhaust tube 9 at the opposite end of the lamp. A fiow of air through the lamp suflicien'tly large to displace the volume therein three times is usually preferred. The heat treatment is terminated by the motion of the head I5 which carries the lamp it from the oven 22 and which causes the air connection to be separated from the head I5 terminating the fiow of air through the lamp I4.

The lamp I I is now by further movement of the head I5 positioned in operative relation to apparatus for tipping-off the exhaust tube 9' which apparatus as shown in Fig. 5 provides the burners 23 and 24 for heating and fusi'ng the ends of sa'id exhaust tube 9' into a solid end or tip. The only remaining opening to the interior of the lamp is then the exhaust tube 9 which is connected to the head I5.

Succeeding operations to the lamp I i provide forthe exhausting, activation of the cathodes I, the flushing, the final exhausting, the filling and the tipping-off of the exhaust tube 9 in that order and as represented by Figs. 5 and 6. The initial exhausting takes place as soon after the baking operation as possible and is the result of another connection made to the lamp it through the head I5 by means such as a rotary valve (not shown) which permits various connections to be made thereto for the required periods of time. The exhausting operation can be started dur-. ing the tipping-off of the tube 9', if desired, and continue for a relatively long period, during the immediate portion of which the lamp may again be heatedto causeliberation of still additional gases etc. included in the lamp parts and during which period it is connected to sources of electrical energy for causing the heating and consequent activation of the coated cathode at each end thereof. The electrical connections are made through a wiping contact made by the leads 8 at both ends of the lamp I4 with the contact strips 25 located adjacent the path of movement the lamp ll cause the introduction of a limited quantity of an lonizable gas, such as neon, and a second quantity of mercury, the discharge supporting material, (the first having been drawn out by the exhaust operations) by means (not shown) connected to the lamp through the head I5. The lamp I4 is then sealed off by the flames from the burners 2B and 21 which separate the exhaust tube 9 and tip it oil. adjacent the end of said lamp I4 completing our method of manufacture.

The complete method of manufacturing the fluorescent lamp I4 as hereinbeiore described can best be practiced by high speed automatic apparatus in order that the successful completion,

of the method can be assured and the resulting advantages hereinbefore referred to realized.

The first step in the method, that represented by Fig. 1 wherein the fluorescent coating is applied to the interior surface of the bulb I, is preferably practiced by the apparatus disclosed, in United States patent application Serial No. 510,-

483, filed November 16, 1943, by John J. Malloy.

Such apparatus provides for the proper coating of the bulb I and drying of said coating under effective controls and contamination prevention conditions.

Succeeding steps in the complete method of manufacturing the fluorescent lamp are preferably performed, by apparatus schematically disclosed in Fig. 7 which apparatus effects the sealing of the mounts 5 and 5' in the open ends of the tubular bulb I as shown in Figs. 2 and 3. The sealing operations are performed between the bulb I and the mounts a and 6' while they are retained in heads on the turret 28 of said apparatus and occur along the course 29 of movement of the heads through a series of work stations. The turret 28 and the work stations which are only schematically represented in the drawing correspond to those of the apparatus disclosed in United States patent application Serial No. 465,008, Frank J. Malloy, filed November 9,

1942, and are associated with the sealing apparatus (not shown) corresponding to thatdof said application and to United States patent applicaof the lamp I4 and head I5 and are made for a sufficient period to cause the coating materials, such as barium carbonate on the cathodes 1. to be changed'to oxides having the desired electron emissive properties. Before the activation of the cathodes is complete, thelamp I4 is flushed by the admission through the head I5 of a quantity of an inert gas, such as nitrogen, or final filling gas and/or a quantity of mercury and then reconnecting said head I5 to another exhaust line. The electrical connections to the lamp it are preferably discontinued during and directly after the flushing operation and are remade tion Serial No. 530,952, Raymond H. Stuart, filed April 14, 1944. The mount 5 and bulb I are introduced into a headof theturret 28 at work station A and are, during the counterclockwise indexing rotation of said turret 28 which advances 'said heads along the course 29, sealed together in the manner indicated in Fig. 2. The indexing motion of the turret 28 is the result of the rotation of the drum-type cam 30 on the main drive shaft-3| of the machine which cam 30 engages rollers :32 (only a few of which appear) indirectly connected in the usual manner to the turret 28 and representative of each head thereon. During the rest period of the head, the regularly shaped portion of the cam 30 is located between two of the rollers 32 whereas during the indexing'periods one of said rollers 32 is carried into a curve channel in the cam 30 and advanced thereby. Repeated indexing motions of the turret 28 carry the bulb I and mount 5 through all of the stations about the turret 28 thereby causing said bulb I and mount ,5.to be sealed togetherand finally again advance the head to station'A where the bulb I is removed from the head and re-inserted in an inverted Dosition together with a second .mount 5'. Sueceeding indexing movements of the turret 28 advances the bulb I and the mount 5' again through the work stations in the course 29 causin them to be sealed together as indicated in Fig. 3. The variousv operations having to do with the insertion. removal and reinsertion of the bulb i and the mounts and 5' into the head of the turret '28 attributed to station A can also be performed at the stations adjacent thereto without interfering with normal sealing operations of the apparatus. The rate of index of the apparatus is such that it is most convenient to remove the bulb 8 from a head taking station A and to reinsert said bulb I in the next head taking that station. Accordingly, every other head on the turret 33 is used in the first sealing operation and the alternate heads are used in the second sealing operation. The final sealing operation is complete when the now unitary combination of bulb l and mounts 5 and 5' take station B in the course of their second passage through the work stations and in this form apear-as the lamp i3 shown in Fig. 4.

The succeeding lamp making operations of our invention are brought about in an adjacent portion of the apparatus into which the lamp I4 is preferably transferred immediately and in this particular instance, automatically by the mechanism 33. The function of the automatic transferring mechanism 33 is-to cause the lamp M to be carried to and treated in the next manufacturing step immediately without allowing it to cool suiliciently to permit water vapor and other contamination to condense and react with the interior parts thereof. The lamp i4 is transferred from station B of the sealing portion of our apparatus to station C of another adjacent portion thereof by a pivoting motion of the transferring mechanism 33 about the vertical shaft 33 which motion is timed to carry the transferring mechanism 33 to station B after every other indexing movement of the turret 23 when completely assembled lamps it appear at said station. The transferring mechanism 33 is moved into operative relation to station B as the lamp I4 is being indexed into this station so that said index causes the lamp Hi to pass between the stationary Jaw 35 attached to arm 36 which is pivoted on the shaft 34 and the movable jaw 81 pivoted on'the screw 38 which extends from said stationary Jaw 35. At such times, the movable Jaw 31 is held at the open position by the link 38 and operating lever 40, the latter of which is pivoted on the screw 4| extending from the arm 36 and takes a position determined by the radial extent of portion 42 of the cam 43 in engagement with the roller 44 on the end of the operating lever- 40. The spring 45 located between posts in the arm 36 and the actuating lever 40 causes, through its contracting force, the operating lever 40 to take a position in agreement with the extent of the portion 42 of the cam 43 engaged .by the roller 44. The transferring of the lamp I4 is initiated by the counterclockwise rotation of the shaft 34 which carries the portion 42 of the cam 43 from engagement with the roller 44 thereby allowing the Jaw 31 to close and grip the bulb l4. The next movement of the transferring mechanism 33 is an upward movement lifting the mount 5' and the exhaust tube 3' at the lower end of the lamp l4 from the confining features of the sealing head at station B and is followed by a counterclockwise swing of the mechanism to the position shown which places the lamp i4 at station C. Both of the last mentioned movements of thetransferring mechanism 33 are 4 caused by corresponding movements of the shaft 34 and are transferred to the arm 36 thereof through friction means (not shown). The transferring mechanism 33 reaches the extent of its swinging movement, the position in which it is shown in Fig. '7, when the stop screw 46 on an ear of the arm 36 engages the stationary post 41 whereupon it again takes a short upward movement, in this instance, inserting the exhaust shaft 34 carries the raised portion 43 of the cam 34 against the roller 44 on the actuating lever 40 causing the mechanism 33 to release the lamp Id. The return swing of the transferring mechanism 33 carrying it to station B as previously described occurs at a time when the indexing motion of the turret 49 (only a fragment appearing in Fig. 7) which supports head l5 (Fig.

the stationary tion B) is reached, the further rotation of shaft 34 turns the cam 43 so that said jaws 35 and 31 are closed by movement of the raised portion 48 of said cam 43 from engagement with the roller 44 on actuating lever 43 and then are opened by the advancementof the raised portion 42 of said cam 43 into engagement with the roller 44. The transferring mechanism 33 is also moved down to its original elevation during the return swing thereof by a corresponding movement of the shaft 34. As hereinbefore noted 'the entire operation of the transferring mechanism 33 is dependent on the movement of the shaft 34, the actuation of which in turn depends on means (not shown) of usual form corresponding to other similar means of the sealing portion of our apparatus and. in this particular instance engaging the main portion of our apparatus drive shaft SI of that associated with station 0. The main drive shaft 5| is also the means of turning the drive shaft 3| of the sealing portion of our apparatus to which it is coupled by the gears 52 and 53 and rotates at half the speed of said shaft 3| to actuate the transferring mechanism 33 and the so far undescribed apparatus at station C in proper timed intervals with respect thereto.

The further treatment of the lamp I4 as previously described in the method takes place while said lamp l4 remains connected to the head 15 of the apparatus presented at station C whichheadi5 and apparatus associated with said treatment correspond very closely with the apparatus disclosed in detail in United States Patent 2,247,513, A. J. Marshaus, July 1, 1941, and only schematically shown in the present connection in Fig. '7. The lamp I4 is held in the head I5 (Fig.

'ments of the supporting turret 49 which is indexed in a counterclockwise direction in a regular manner. Each head is about the turret 49 is represented by a roller 56 in a common form of indexing means and is advanced by such rotation of the main drive shaft 5| as carries oneof .said rollers 56 into the curved channel in cam 51 and finally to the former position of the preceding roller 55. The regular form of the remainder ofithe cam 51 fits relatively tight between two and head carry said lamp I4 through several stations and finally to a station within the oven 22 and produce a corresponding rotation of the rotary valve 58 and alignment of passages therein, to which said head I5 is connected through thepiping 59. At such times, the lamp I4 is subjected to the heat of the oven '22 which is maintained at a sufficiently high'temperature to burn out the binding material and drive out such occluded gases and other contamination contained within the lamp parts and is, through the aligned passages in therotary valve 58, subof the rollers 56 during the further rotation of v Jected to the flushing effect of air forced into it from a source (not shown) through said passages piping 59, head I5. and exhaust tube 9. The air and contamination are exhausted or discharged out the exhaust tube 9' at the opposite end of said lamp I4. Succeeding indexing movements of the head l5 continue the treatment of the lamp I4 as the oven 22 extends along the course of movement thereof and the passages within the rotary valve 58 have an arcuate form which continues the air connection to the head I5 therethrough.

. The heating and flushing operations to the I lamp I4 are terminated by the index of the head I5 beyond the oven 22 and to operative relation to the tipping means provided by the burners 23 and 24. At such times the air connection is 7 broken to the head I 5 by the rotary valve 58 and another connection is made in a similar manner through the rotary valve 58 and piping 59 which exhausts said lamp I4. The function of the tipping means is to seal off the exhaust tube 9' permanently and to prevent any influx of water vapor and other contamination into the lamp I4 during the immediate operation of the apparatus aswould normally occur as the interior .of said lamp I4 cools.

A following indexing movement of the turret 49 does not disturb the exhaust connection through the rotary valve 58 but carries the leading-in wires 8 at opposite ends of the lamp I4 intoengagement with contact strips 25 at said ends and at opposite sides of the path of movement thereof so that electrical connections are made to each of the leads 8 separately. Other electrical connections (not shown) made to the contact strips 25 causes sufllcient electrical potential to be applied across the cathodes l at both ends of the lamp I4 to heat them to a temperature causing a coating such as barium carbonate, thereon to have the proper electron emissive properties. The connections are such that there is no appreciable difference in potential between cathodes I at opposite ends ofthe lamp I4 and no tendency for a discharge to form through the length thereof. The exhaust and electrical connections are retained through several succeeding indexing movements without change and the lamp l4 continues to be exhausted and the cathodes I to be activated.

A change in the manufacture occurs when the head I5 indexesinto a station where a mercury dispenser (not shown) in combination with the head I5 is positioned in operative relation to stationary actuating means 60 overlying the turret 49 and head I5 and where the leads 8 at both ends of said lamp I4 engage separate sections 6I--5I of the contact strips 25. The dispenser is 10 preferably of the construction and in the combination of apparatus disclosed in the Marshaus Patent 2,247,513 hereinbefore referred to and prov vides the lamp I4 with a measured quantity of mercury on operation by the actuating means 6|! during the period the head l5 remains at the present station. At such times, the actuating means 80 is operated by means (not shown) properly timed with the operations of the entire apparatus by the movements of the drive shaft 5|. The movement of the leads 8 into engagement with the sections 8I5I of the contact strips 25 terminates the heating of the cathodes 'l as said sections are insulated from the other sections of the contact strips 25 and from all sources of electricity. The exhausting operation is preferably continued at the present station although in certain instances it may be desirable to interrupt said operation to assure the movement of mercury into the lamp I4.

The succeeding indexing movement of the head I5 carries it from operative relation to the merc1 dispenser actuating means 50 and to a station where the leading-in wires 8 at opposite ends of the lamp I4 engage other sections 62- -62 of the contact strips 25 which apply full operating voltage to the cathodes I. As before, the exhaust connection is continued through the piping 59 and the rotary valve 58.

The following .two stations are occupied by still other sections 55-55 of the contact strips 25 which are connected to a source of electricity broken by the indexing movement of the head l5 which advances it beyond the ends of thecontact strips 25, a movement which in this particular instance again causes the lamp I4 to be advanced to a station within an oven 54 and to be heated. The exhaust connection to the lamp I4 is continued during the movement to remove the oc-- cluded gases and other materials detrimental to lamp life which are released from said lamp I4 by the present head treatment. The heating and exhausting treatments also continue through succeeding indexing intervals and thoroughly clean the lamp l4 of all exhaustible materials by the time the head I5 is advanced to the last station within the oven 64. In the course of the movement to the last mentioned station, the rotary valve 58 is turned so that it breaks the exhaust connection to the lamp I4 and makes another connection. also completed through the piping 59,

which causes the admittance of a specific amount of an ionizable gas giving the lamp I4 the required characteristics. A second mercury dispenser actuating means 65 is located at the last station occupied by the oven 54 and in operation releases the required dosage of mercury. the discharge supporting material of the specific lamp I4, to the head I5 which mercury is assisted in its movement through the exhaust tube 9 and into I the lamp l4 by the-influx of gas thereinto. In certain instances. the lamp I4 may retain suflicient heat from its treatment in the oven 22 so that the heating operation produced by oven 64 the lamp I4 through the rotary valve 58 and carries said lamp I4 into operative relation to the tipping-off device 66 located at the next station.

The function of this device 88 is to seal the lamp I4 following the final treatment and introduction of the gas and mercury filling therein by fusing and tipping-oil the exhaust tube 9 by which it is connected to the upper part of the head IS. The exhaust tube 9 is stretched in the tipping-oil. operation by a longitudinal movement of the lamp I4 which is then entirely supported'by the Jaws 54 and 55 of the head I5 and is separated from the stub of the exhaust tube 9 retained in the upper part thereof. After completion of the tipping-oil operationand the disengagement of the device 66, the head i5 is indexed in turn through two succeeding stations which are unoccupied by apparatus and allow the completed lamp l4 and the stub of the exhaust tube 9 to be removed from the apparatus. The index of the head I5 beyond these unloading stations brings the head I5 again into station C and starts it on a succeeding cycle of operations like that just described.

The embodiment of our apparatus schematic disclosed in Fig. 8 separates the greater portion of the heating treatment apparatus from the exhaust and filling apparatus thereby reducin the injurious effect of the heat on the rubber parts thereof. The present apparatus also provides a higher possible rate of. production and allows longer periods of heat treatment than that previously described and such other advantages that will appear in the description thereof which follows. As in the previously described apparatus, the bulb I and mounts 5 and 5' are sealed together to form the lamp I4 in apparatus arranged at work stations about an indexed turret 61 in the manner disclosed in United States patent applications Serial No. 465,008, F. J. Malloy, filed November 9, 1942, and Serial No. 530,952, R. H. Stuart, filed April 14, 1944, hereinbefore referred to. The bulb I and mount 5 are manually introduced in a head 68 on the turret 81 at either stations D or E and are brought into operative relation to the burners 69 located at various work stations in the course of the movements of said turret 61. Air nozzles are provided at the first six stations occupied by the burners 69 to direct air into upper end of the bulb I, before it becomes sealed to the mount 5, to prevent the exhaust gases given off by the flames from said burners 69 from entering the bulb I. The motion of the turret 61 carries the sealed bulb I and mount 5 finally to stations F and G which are unoccupied b other apparatus and which are used in' the manual removal of the unitary bulb I and mount 5. The mount 5' is sealed over the open end of the bulb I in a second vpassage through the work stations about the turret 81 during which the air nozzles 10 direct air into the lamp through the upper exhaust tube 9 after said bulb I is turned end-for-end and reinserted together'with .the mount 5' into the head 88 at either station D or E. As in the manufacture of the lamp in-the previously described apparatus, the bulb I and mount 5 are preferably introduced into certain alternate heads 68 on the turret 81 and the bulb I and mount 5' are inserted in the inbetween heads 68 so that each of said last mentioned heads 68 advances a completely sealed lamp I4 to sta- 12 tion H after passing through the work stations occupied by the sealin burners 69.

The lamp I4 is removed from the head 68 at station H by the automatic transferring mecha-' nism 1i) (corresponding to such mechanism in combination with the apparatus in Fig. 7) which is driven from the same source (not shown) as the turret 61 inorder to cause it to operate every other time a head 68 advances to said station and a completely sealed lamp l4 takes said station. The transferring mechanism 10 is operated about the vertical shaft H. by which it is controlled, and takes a vertical upward motion separating the mount 5' from the head 68 of the sealing .apparatus, swings to the delivery position shown, releases the lamp I4 and returns to the original position at station H at proper intervals to avoid interference with the movements of the lamp I4 and apparatus at both the receiving and delivery stations. The release of the lamp I4 is effected through the movements of the jaw 12 which separates from the lamp I4 sufficiently to allow the mechanism 10 to make the return swing without disturbing the lamp I4 however the mechanism 10 must take station H prior to the movements of the succeeding lamp I4 to prevent the stationary jaw 13 from interfering therewith.

The lam I4 transferred by the mechanism I0 is introduced in a head 14 on the turret 15 which provides for the advancement thereof in indexing movements in a counter clockwise direction through another series of work stations and is held in place in the head 14 by any suitable gripping means. The indexing movement of the turret 15 is effected by means (not shown) like the corresponding means shown schematically in Fig.

7 which means is operated by the main driving means (not shown) also operating the sealing turret 61 and 'all other portions of the apparatus. The course of movements of the head 14 carry the lamp I4 into the oven 16 which is maintained at a sumciently high temperature to cause the lamp I4 to be heated to a degree causing 'the binder of the fluorescent coating to burn so as to be separated therefrom. The increase in the temperature of the lamp occurs quite rapidly and the burning is in progress when said lamp I4 is advanced below the first of a series of nozzles 11 which are located at succeeding stations and which direct a stream of air into the upper end of the exhaust tube 9. A corresponding discharge of air occurs from the exhaust tube 8' at the bottom of the lamp l4 so that a slight current of air passes through the length of the lamp I4 flushing the combustion products therefrom. The combustion products and such other exhaustible contamination within the lamp are substantially all removed therefrom by, the time the indexing movements carry said lamp I4 from below the last air nozzle 11 and no means are provided for continuing circulation of air during the movements of said lamp I4 through the still other work staoperations and consequently allows no appreciable time for the heated lamp parts to cool and absorb moisture and other contamination.

The present transfer of. the lamp l4 from station J is effected'by the mechanism 11 which swings about the vertical shaft 18 to operative relation with said station during the index of turret Illso that the lamp i4 is carried into the pocket in the stationary jaw 19 thereof. The movable law 80 of the transfer mechanism 11 is then caused to grip the lamp l4 through rotation of the shaft 18 and cam Si in a manner described in connection with the other transfer mechanisms and is swung to the delivery position in which it is shown where said lamp id is positioned in proper alignment with the head 15. A following upward movement of the transfer mechanism 11 inserts thee'xhaust tube 9 at the top of the lamp l4 into the head l which corresponds to that shown in Fig. 4 whereupon jaws (shown at 54 and 55 at an adjacent'station) of the head l5 close on the lamp l4 and grip it. The remainder of .the'cycle of operation of the transfer mechanism 11 is completed by' the opening motion of the movable jaw 80 and the return swing of the mechanism I1 which carries it away from the head 15' and immediately to operative relation to a head ll of the previously described apparatus in a succeeding cycle of operation. v

The portion of our apparatus receiving the lamp and heretofore referred to only iniconnection with the head I 5' provides for the exhausting, further treatment, fillin and final sealing of the lamp H and is essentially that disclosed in United States Patent 2,247,513 hereinbefore referred to. The various operations of the apparatus occur during the indexing movements of the head IE to work stations to which the head I5 is carried by the turret 49' (only partially shown) which motion is produced in the turret 49' by the main driving means (not shown) in order to be in synchronism with the other parts of the apparatus. The indexing movements of the head I-5 first bring the lamp ltto a station where the exhaust tube 9' at the lower end of the lamp I4 is sealed off by the. flames from the burners 23' and 24' in the manner described in connection with Fig. 5 and then advance it to another station where the lamp M is heated by the oven 82 and is exhausted by means connected thereto through the head l5 and rotary valve 83. The heat treatment rlds the occluded gases from the parts of the lamp l4 so that they can be removed therefrom by the exhaust and is succeeded, when the indexing movements of the turret 49 carry the lamp l4 beyond the oven 82, by treatments to the cathodes I at opposite ends of the lamp l4 produced'iby the passage of electricity through said cathodes I, the results of wipingconnections made to the contact bars 25' bythe leading-in wires 8. The treatment to the cathodes 1 consists in the heating thereof by electricity to cause the coating thereon to change to an oxide having electron emissive properties and initiates a course of treatment duplicating that performed in exactly the same manner in the apparatus shown in Fig. 7. The exhaust and cathode treatment continue during the succeeding indexing movements of the head l5 without interrupgagement with the sections SI of the contact strip 25' interrupts the cathode treatments since said sections 6| are'not connected to any source of electricity. The exhaust connection continues as in the previous stations. Further indexing movements of the head I! carry the leading-in wires 8 into engagement with the sections 82' of the contact strips 25' and then into engagement with the sections 63' thereof thereby causing further heat treatment of the cathodes I and a temporary end-to-end discharge in the lamp ll. Still further indexing movements of the head l5 advance the lamp i4 into the oven 64', breaks the exhaust connection thereto through the rotary valve 83 and causesthe proper gas and mercury filling to enter the lamp through the adjustment of the rotary valve 83 and the operation of the dispenser actuating means 65'. Final treatment to the lamp I4 occurs whenit is carried into operative relation to the tipping-oil device 66" which sealsthe lamp ll by fusing an intermediate section of the exhaust tube 9 into a permanent tip. The lamp ll and the remainder of the exhaust tubes are removed from the jaws I4 and and the upper portion of the head I! at the two following work stations which are the final stations taken by the head I! in one cycle of operation of the apparatus. The head I!" begins another repeated cycle of operation in the next index which carries it into position to receive another lamp from the transfer mechanism.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. The method of manufacturing electric fluorescent lamps in a sequence of operations which comprises heatin a'partially manufactured lamp,

. thereof an ionizable gas and a discharge supporttion until the head 15' passes to astation where i the contact strips 25'. At this station, the automatic operation of the dispenser actuating means 60' causes acontrolled quantity of mercury to be discharged through the head l5 and the exhaust tube 9 to the interior of the lamp l4 and the ening material through the passage, and thereafter sealing the passage in the lamp to permanently seal said lamp.

2. The method of manufacturing electric fluorescent lamps in a sequence of operations which comprises immersing a partially manufactured lamp having a bulb with a coating of a fluorescent material and a binder on the interior thereof and having a passage through to said interior in a heated gaseous atmosphere to cause the binder to burn and be separated from the coating. exhaust ing the lamp through the passage directly following the heating operation before said lamp cools appreciably to remove all exhaustible materials therefrom, introducing into the lamp immediately after the final exhaustion thereof an ionizable gas and a discharge supporting material through the passage, and thereafter sealing the passage in the lamp to permanently seal said lamp.

3. The method of manufacturing electric fiuorescent lamps in a sequence of operations which comprises heating a. partially manufactured lamp having a bulb with a coating of a fluorescent material and a binder on the interior thereof and having a passage through to said nterior to cause the binder to burn and be separated from the coating, exhausting the lamp during the heat treatment thereof to remove the combustion products and the occluded elements released by the heat treatment therefrom, directly thereafter and before said lamp cools appreciably more completely exhausting the lamp to remove the atmospher from said lamp, introducing into the lamp immediately after the final exhaustion thereof/an ionizable gas and a discharge supporting material through the passage, and thereafter sealing the passage in the lamp to permanently seal said lamp. J

4. The method of manufacturing electric fluorescent lamps in a sequence of operations which comprises heating a partially manufactured lamp, having a bulb with a coating of a fluorescent material and a binder on the interior thereof and having electrode mounts with passages therethrough to said interior at opposite ends of said bulb, to cause the binder to burn and be separated from the coating, and concomitantly flushing the interior of the lamp to remove the combination products with a gaseous medium introduced in and exhausted from said lamp through the passages in the electrode mounts at opposite ends thereof.

5. The method of manufacturing electric fluorescent lamps in a sequence of operations which comprises heating a partially manufactured lamp having a tubular bulb with a coating of a fluorescent material and a binder on the interior thereof and having passages through to said interior at opposite ends of said bulb to cause the binder to burn and be separated from the coating, concomitantly flushing the interior of the lamp to remove the combustion products with a aseous medium introduced in and exhausted from said lamp through the passages at opposite ends thereof, sealing the passag at one end of the lamp and exhausting the interior of the lamp through the other passage directly following the heating operation before said lamp coolsappreciably to remove the atmosphere, and thereafter introducing an ionizable gas and a discharge supporting material therein through the said other passage in said lamp, and sealing the last mentioned passage in the lamp to permanently seal said lamp.

6. The method of manufacturing electric fluorescent lamps in a sequence of operations which comprises heating a partially manufactured lamp, having a tubular bulb with a coating of a fluorescent material and a binder on the interior thereof and having electrode mounts with exhaust tubes communicating with passages through to said interior sealed to the opposite ends or said bulb, to cause the binder to burn and be separated from the coating, flushing the interior of the lamp to remove the combustion products during the heating operation with a gaseous medium introduced in and exhausted from said lamp through the exhaust tubes at opposite endsthereof, sealing the exhaust tube at one end of the lamp and exhausting the interior of the lamp through the open exhaust'tube directly after the heat treatment while said lamp is stil1 at nearly maximum temperature to remove the atmosphere, introducing an ionizable gas and a discharge supporting material in the lamp through the last mentioned exhaust tube to give said lamp the desired operating characteristics, and seal? ing the last mentioned exhaust tube to permanently seal the lamp.

7. The method of manufacturing electric fluorescent lamps in a sequence of operations which comprises heating a partially manufactured lamp, having a tubular bulb with a coating of a thereof and having electrode mounts with unactivated cathodes thereon sealed to the opposite ends of said bulb, one of said mounts having a passage therethrough giving access to said interior, said heating being sufficient to cause the binder to burn and become separated from the coating, exhausting the atmosphere and other materials from the interior of the lamp through the passage in the electrode mount directly following the heating operation before said 'lamp cools appreciably, connecting a source of electricity to the electrode mounts to heat and cause activation of the cathodes thereof during said exhaust operation, introducing an ionizable gas and a discharge supporting material into the lamp through the passage in the mount to give said lamp the desired operating characteristics, and thereafter sealing the passage to permanently seal the lamp.

8. The method of manufacturing electric fluorescent lamps in a continuous uninterrupted sequence of operations which comprises sealing electrode mounts to opposite ends of a tubular bulb provided with a coating of a fluorescent material and a binder, one of said mounts having an exhaust passage therethrough connected to an exhaust tube and giving access to the interior of the lamp, heating the full length of the lamp to caus the binder in the coating to burn and be separated from the bulb and the occluded gas to be driven therefrom, exhausting the atmosphere and other materials from the interior of the lamp by means of the exhaust tube directly following theheating operation before the lamp cools appreciably, introducing an ionizable gas and discharge supporting material into the lamp through the exhaust tube to give said lamp the desired operating characteristics. and sealto permanently seal the nected to an exhaust tube and giving access tothe interior of the lamp, heating the lamp to cause the binder in the coating to burn and be driven from the bulb, exhausting the atmosphere and other materials from the interior of the lamp by means of the exhaust tube directly following the heating operation before the lamp cool appreciably, introducing an ionizable gas and a discharge supporting material into the lamp through the exhaust tube to give the lamp the desired operating characteristics, and thereafter sealing the exhaust tube to permanently seal the lamp.

10. The method of manufacturing electric fluorescent lamps in a sequence of operations which comprises applying to the inner surface of an open ended tubular bulb a coating of a fluorescent material and a binder, sealing electrode mounts having exhaust passages therethrough connected to exhaust tubes to opposite ends of I at one end of the lamp and exhausting the lamp through the other exhaust tube directly following the heating operation before said lamp cools appreciably, and then filling the lamp with the proper quantities of ionizable gas and a discharge supporting material through the said other exhaust tube, and sealing the last mentioned exhallst tubelto permanently seal the lamp.

11. The method of manufacturing electric fluorescent lamps in a sequence of operations which tive "sealing operations to increase the air pressure in the bulb an'd'prevent the entrance of contaminating gases thereinto during formation of the seal, heating the lamp to cause the binder in. the coating to burn and be separated from the bulb, concomitantly flushing the lamp with air directed into the exhaust tube at one end thereof and exhausting it together with the products of combustion from the exhaust tube at the other end of the lamp, sealing the exhaust tube at one end of the lamp and exhausting the lamp through the other exhaust tube directly following the heating operation before said lamp cools appreciably, and then filling the lamp with the proper quantities of ionizable gas and a discharge supporting material through said other exhaust tube, and sealing the last mentioned exhaust tube v to permanently seal the lamp.

12. The method of manufacturing electric fluorescent lamps in a sequence of operations which comprises flushing the inner surface of an open ended tubular bulb with a coating fluid of a fluorescent material and a binder, allowing the excess fluid to drain from th bulb and the remainin coating todry; sealing electrode mounts having exhaust passages connected to exhaust tubes to opposite ends of the bulb to complete the lamp structure, immediately heating the lamp tocause the binder in the coating to burn and be separated from the bulb,'fiushing the lamp during the heating operation with air directed into the exhaust tube at one end thereof and exhaustinfl together with the combustion products from the exhaust tube at the other end thereof, sealing the exhaust tube at one end of the lamp before said lamp cools appreciably, immediately exhausting the lamp through the remaining open exhaust tube before said lamp cools appreciably,

' filling the lamp with an ionizable gas and a discharge supporting material. and sealing the last mentioned exhaust tube to permanently seal the lamp. Y

13. Apparatus for manufacturing electric fluorescent lamps comprising means for carrying a lamp, having a coating of a fluorescent material and 'a binder on the interior-thereof and a pair of exhaust tubes communicating with said interior, in a continuous course of movement to a sequence of work stations, an oven located at one of the stations for heating the lamp, to cause the binder to burn and separate from the fluorescent material, means at the last mentionedstation for directing air through one of the exhaust tubes of the lamp to flush the combustion products within the interior out through the other exhaust tube thereof, means at an immediately succeeding station for fusing and sealing one of 18- the exhaust tubes, means at succeeding stationsfor making a gas-tight connection to the unsealed exhaust tube and causing the exhaustion and then the introduction of an ionizable gas and a discharge supporting material into the lamp directly after said lamp is heated in the oven and before it cools appreciably, and means at the latter of th last mentioned stations for fusing and sealing the last mentioned exhaust tube to seal and complete the manufacture of the lamp.

14. Apparatus for manufacturing electric fluorescent lamps comprising a head for holding a lamp, having a coating of a fluorescent material and a binder on the interior thereof, and making a gas-tight connection to one of a. pair of exhaust tubes communicating with' said interior. a carrier for supporting and. advancing th head in a continuous course of movement to a sequence of work stations, an oven located at one of the stations for heating the lamp to cause the binder to burn and separate from the fluorescent-him terial, means connected to the head at the last mentioned station for causing air to be directed through the exhaust tube engaged thereby to the interior of the lamp to flush the combustion products within the interior out the other exhaust tube thereof, means at an immediately succeed- I ing station for fusing and sealing the last mentioned exhaust tube, means connected to the head at succeeding stations for causing the exhaustion and then the introduction of an ionizable gas and a discharge supporting material into the lamp directly after said lamp is heated in the oven and before it cools appreciably, and means at another succeeding station for fusing and sealing the last mentioned exhaust tube to seal and complete the manufacture of the lamp.

15. Apparatus for manufacturing electric fluorescent lamps comprising a carrier for advancing a lamp, having a coating of a fluorescent material and a binder on the interior thereof and a pair of exhaust tubes communicating with said interior, in a course of movement, an oven located along the course of movement for heating the lamp to cause the binder to burn and separate from the fluorescent material, means in combination with the oven for directing air through one of the exhaust tubes of the lamp to flush the combustion products from the interior-and out the other exhaust tube thereof, a second carrier for holding and advancing the lamp to a sequence of work stations located adjacent the first carrier, a transferring mechanism for removing the lampadvanced beyond the oven from the first carrier and immediately inserting it in the second carrier, means at a station of the second carrier for fusing and sealing one of the exhaust tubes, means for making a gas-tight connection to the unsealed exhaust tube at succeeding stations and causing the exhaustion and then the,

introduction of an ionizable gas and a discharge supporting material into the lamp, and means at the latter of the lastmentioned stations for fusing and sealing the last mentioned exhaust tube to seal and complete the manufacture of the lamp.

18. Apparatus for manufacturing electric fluorescent lamps comprising sealing apparatus for fusing electrode mounts having exhaust tubes communicating with passages therethrough to opposite ends of a tubular bulb having a coating of a fluorescent material and a binder on the interior thereof to completea lamp, means located adjacent the sealing apparatus for carrying a mentioned means for heating the lamp to cause.

the binder to burn and separate from the fluorescent material, means at the last mentioned station for directing air through one of the exhaust tubes of the lampto flush the combustion products Within the interior out through the other exhaust tube thereof, means at a succeeding station for fusing and sealing one or the exhaust tubes, means for making a gas-tight connection to the unsealed exhaust tube at succeeding stations and causing the exhaustion and then the introduction of an ionizable gas and a discharge supporting material into the lamp, 'and means at the latter of the last mentioned stations for fusing and sealing the last mentioned exhaust tube to seal and complete the manufacture of the lamp.

1'7. Apparatus for manufacturing electric fluorescent lamps comprising sealing apparatus for fusingelectrode mounts having an exhaust tube communicating with a passage therethrough to opposite ends of a tubular bulb having a coating of a fluorescent material and a binder on the interior thereof, said sealing apparatus comprising means for supporting said bulb and an electrode mount in sealing relation, burners for directing fires against contiguous portions of the bulb and mount to seal them together, means for directing air into the interior of the bulb to prevent the combustion products from entering and contaminating the interior of the lamp, means located adjacent the sealing apparatus for carrying a lamp in a continuous course of movement 40 to a-sequence of work stations, transferrin mechanism located in operative relation to the sealing apparatus and the last mentioned means for removing the lamp from said sealing apparatus and inserting it in said last mentioned means, an oven located at one 01 the'stations of the last mentioned means for heating the lamp to cause the binder to burn and separate from the fluorescent material, means at the last mentioned station for directing air through one of the exhaust tubes of the lamp to flush the combustion products within the interior out through the c other exhaust tube thereof. means at a succeeding station for fusing and sealingoneof the exhaust tubes, means for making a gastight connection to the unsealed exhaust tube at succeedin stations and causing the exhaustion and then the introduction of an ionizable gas and a discharge supporting material into the lamp, and means at the latter of the last mentioned stations for fusing and sealing the last mentioned exhaust tube to seal and complete the manufacture of the lamp.

HAROLD D. BLAKE. WILFQRD J. WINNINGHQFF.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 2,006,818 Zimber' July 2, 1935 2,154,550 White Apr. 18, 1939 2,247,513 Marshaus July 1, 1941 2,279,907 Atchley Apr. 14, 1942 2;303,-290 Michael Nov. 24, .1942 2,318,060 Cortese' May 4, 1943 Johnson Nov. 16, 1943 

